Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G11/00—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
  • C10G11/14—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts
  • C10G11/16—Catalytic cracking, in the absence of hydrogen, of hydrocarbon oils with preheated moving solid catalysts according to the "moving bed" method
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/40—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the pentasil type, e.g. types ZSM-5, ZSM-8 or ZSM-11, as exemplified by patent documents US3702886, GB1334243 and US3709979, respectively
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/80—Mixtures of different zeolites
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
  • B01J2229/10—After treatment, characterised by the effect to be obtained
  • B01J2229/26—After treatment, characterised by the effect to be obtained to stabilize the total catalyst structure
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
  • B01J2229/30—After treatment, characterised by the means used
  • B01J2229/36—Steaming
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2229/00—Aspects of molecular sieve catalysts not covered by B01J29/00
  • B01J2229/30—After treatment, characterised by the means used
  • B01J2229/42—Addition of matrix or binder particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J29/00—Catalysts comprising molecular sieves
  • B01J29/04—Catalysts comprising molecular sieves having base-exchange properties, e.g. crystalline zeolites
  • B01J29/06—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof
  • B01J29/08—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof of the faujasite type, e.g. type X or Y
  • B01J29/084—Y-type faujasite

Definitions

• the invention is an improvement in the moving bed catalytic cracking process.
• Catalytic cracking of hydrocarbons with zeolite containing catalyst is a well known process.
• the hydrocarbons contact fluidized catalyst, and are cracked to lighter products.
• the catalyst is deactivated by coke deposition, necessitating regeneration of coked catalyst in a regenerator.
• thermofor process is the moving bed analog of the fluidized bed FCC process.
• the catalyst regeneration In the moving bed regeneration zone associated with the thermofor catalytic cracking unit, the catalyst regeneration usually proceeds in stages. Hydrocarbons are burned off in the top of the moving bed regeneration zone, while coke that is present is usually not removed until further along in the moving bed catalyst regeneration zone. The hydrocarbons are relatively easy to burn off. The coke on the catalyst is much more refractory, and is usually not removed until higher temperatures and/or higher oxygen partial pressures are experienced, conditions which usually occur lower down in the moving catalyst regeneration bed.
• FCC and TCC thermalfor catalytic cracking, or moving bed cracking units used amorphous catalyst.
• zeolites were introduced into the catalyst.
• zeolite cracking catalyst Relatively large pore zeolites were used.
• the first zeolite added to cracking catalyst was rare earth exchanged X-type faujasite. This was soon replaced by Y-type faujasite which, because of its higher SiO 2 /Al 2 O 3 ratio was more thermally and hydrothermally stable.
• Numerous improvements have since been made in zeolite cracking catalysts, but no generic zeolite change or addition has been introduced. Typical of later improvements has been the use of HY, the hydrogen form of Y-type faujasite, and more recently USY, a stabilized form of HY in commercial catalysts. Other changes have involved matrix reformulations for improved thermal and hydrothermal stability and metals tolerance.
• the ZSM-5 catalyst resulted in increased production of dry gas, some loss of gasoline yield, and an increase in octane number.
• ZSM-S catalyst especially, virgin catalyst, has exceedingly high activity.
• researchers have attempted to take advantage of the super activity of fresh ZSM-5 catalysts by adding only small amounts of it to FCC catalyst. Typical of such work is U.S. Patent 4,309,280 which taught adding very small amounts of powdered neat ZSM-5 catalyst, characterized by a particle size less than 5 microns.
• ZSM-S is exceedingly active, and addition of even small amounts results in greatly augmented production of dry gas, at the expense of gasoline yield.
• ZSM-5 is a known additive, as discussed above, and has even been compounded with extruded catalyst suitable for use in moving bed catalytic cracking units, such use has never occurred commercially in moving bed cracking units, at least so far as is known. It is believed that one reason such use has not occurred is that if the entire catalyst inventory in a moving bed cracking unit was dumped, and replaced with catalyst containing, e.g., 2.5 wt % ZSM-5, 10 wt % REY, and the remainder being clay or other binder, the downstream processing equipment could not handle all the gas that would be produced.
• ZSM-5 containing catalyst Gradual addition of ZSM-5 containing catalyst is a way to overcome some of these difficulties. It would be possible to add ZSM-5 containing catalyst to a TCC unit by removing, on a daily basis, about 0.5 to 1% of the circulating catalyst inventory, and replacing it with catalyst containing the desired amount of ZSM-5, e.g., Z.5 wt %. The only problem with such an approach is that it would take from six months to two years to completely replace the catalyst inventory on such a piecemeal basis. Such an approach would avoid overloading the system with fresh ZSM-5.
• the present invention provides a method of adding ZSM-5 containing catalyst into a moving bed catalytic cracking unit containing a circulating catalyst inventory of conventional cracking catalyst to produce an equilibrium catalyst containing a desired ZSM-5 content comprising:
• the process uses a moving bed of catalytic cracking catalyst. Catalyst moves from the catalytic cracking reactor to a moving bed regenerator, and from there back to the reactor.
• the oil chargestock to the process is passed over the moving bed of catalyst and is catalytically cracked to lighter products.
• the catalyst is deactivated by coke deposition.
• Coke deposition is removed from the catalyst in a moving bed regenerator associated with the moving bed cracking unit.
• the cracking catalyst can be any conventional cracking catalyst now used or hereafter developed. Relatively large pore zeolites in clay or other matrix material are preferred. It is also possible, and acceptable, to use ultrastable Y, ultrahydrophobic Y, and other conventional large pore catalytic cracking materials.
• Suitable cracking catalysts contain 1 to 30 wt % large pore zeolite material, preferably a low sodium, rare earth exchanged Y-type zeolite. Very good results are obtained when the catalyst has 5-15 wt % REY zeolite in the matrix.
• the equilibrium catalyst is a conventional TCC catalyst which contains from about 0.5 to 20 wt % ZSM-5.
• the equilibrium TCC catalyst will contain 0.1 to 20 wt % ZSM-5, preferably with 1 to 7 wt % ZSM-5.
• the equilibrium catalyst may be in any size and shape which has been suitable for moving bed catalytic cracking, and may be either amorphous or zeolitic. Preferably it is a zeolitic catalyst in an amorphous base. Very good results are obtained when the conventional TCC catalyst contains from 8 to 16, and preferably 10 to 12 wt % REY zeolite in a clay base.
• the equilibrium catalyst can be in the form of oil dropped spheres, prilled balls, pills or extrudates.
• ZSM-5 is a well known zeolite, fully described in U.S. Patents 3,702,886 and Re 29,948.
• the ZSM-5 will be ion exchanged with ammonium ions and then calcined to place it in the hydrogen or active form.
• the techniques of ion exchange, calcining, and catalyst manufacture are all conventional and form no part of the present invention.
• the changeover catalyst as distinguished from the equilibrium ZSM-5 catalyst, is relatively rich in ZSM-5.
• the ZSM-5 rich catalyst, or changeover catalyst contains 1.5 to 10 times the amount of ZSM-5 contained in the equilibrium catalyst.
• the changeover catalyst may contain 3.75 to 25 wt % ZSM-5.
• the changeover catalyst might contain from 7.5 to 50 wt % ZSM-5.
• the changeover catalyst contains about 1.75 to 4 times as much ZSM-5 as the equilibrium catalyst.
• the ZSM-5 is meant to be an additive to the conventional large pore zeolite, rather than a total replacement for the large pore zeolite. It is believed that best results are achieved when the large pore zeolite, e.g., REY, content is reduced to compensate for the cracking activity afforded by the ZSM-5.
• ZSM-5 can act as a partial substitute for the REY zeolite on a 1:1 to a 1:10 basis.
• 2 weights of ZSM-5 will replace 1 weight of conventional zeolite in the catalyst.
• the conventional TCC catalyst contains 12% REY, and 2% ZSM-S was added to the changeover catalyst, it would be beneficial to reduce the REY content from 12 wt % to 11 wt %.
• the total zeolite content of the changeover catalyst would increase slightly (from 12 wt % REY to 13 wt %, consisting of 11 wt % REY plus 2 wt % ZSM-5) but the overall catalytic activity of the catalyst would not change greatly.
• the changeover catalyst contains 5% ZSM-5, it would be beneficial to reduce the REY content of the changeover catalyst from 12 wt % down to 9-10 wt % REY.
• Changeover catalyst addition can be done on any convenient schedule, e.g. removing from 0.25 to 20% per day. It can be done on a very slow basis, replacing, e.g., the 0.25 wt % per day of the catalyst inventory lost due to attrition and catalyst circulation with changeover catalyst.
• the only disadvantage to such approach is that it would take a long time to see the ZSM-5 in the unit.
• ZSM-5 maintenance rather than addition, can be practiced.
• ZSM-5 maintenance means the addition of sufficient ZSM-5 catalyst, and conventional cracking catalyst, to maintain at approximately a steady state level the ZSM-5 content of the TCC catalyst inventory.
• the desired equilibrium in ZSM-5 level is, e.g., 2.5 wt %
• this level can be maintained by adding equilibrium catalyst containing 2.5 wt % ZSM-5 and the desired amount of large pore zeolite.
• equilibrium catalyst addition by, e.g., mixing on a SO-SO basis changeover catalyst with conventional (non-ZSM-S containing) cracking catalyst.
• catalyst addition for one day can be of ZSM-5 rich catalyst (changeover catalyst) followed by one or two days of conventional (non-ZSM-5 containing) cracking catalyst addition.
• changeover catalyst and equilibrium catalyst is the same distinction between attaining a desired ZSM-5 concentration in the catalyst and maintaining that concentration once it has been attained.
• This unit had a 315 metric ton (347 ton) catalyst inventory.
• the conventional catalyst in the unit had the following specifications.
• the changeover catalyst had the following properties:
• this unit required makeup catalyst rates of 1.13 metric tons (1.25 tons) per day.
• the makeup catalyst rate is set to satisfy those catalyst losses due to attrition, and also to maintain catalyst activity.
• Catalyst addition was usually maintained at 1.8 metric tons (2 tons) per day, although there were short periods of addition rates as high as 3.6 metric tons (4 tons) per day.
• Feed properties are reported hereafter. The numbers reported are approximate because the feed was a blend of different crudes, and the blend varied somewhat.
• the circulating catalyst had, on average, slightly less than 2.5 wt % ZSM-S. Roughly half the catalyst inventory had been replaced with changeover catalyst which was rich in ZSM-S.
• the ZSM-5 addition technique of the present invention resulted in significantly less dry gas production than would have been anticipated from the prior art.
• Table 1 show that the production of light gases goes up by less than 10%, with the addition of 2.5 wt % ZSM-5.
• addition of 0.25 wt % ZSM-5 resulted in approximately a 50% increase in dry gas production.
• the feedstock was a gas oil fraction having the approximate properties reported earlier.
• the changeover catalyst used in the laboratory test was the same changeover catalyst used in the commercial test.
• the catalyst addition scheme used was designed to rapidly bring the ZSM-5 content of the circulating or equilibrium catalyst to the desired level well before 72 days of operation.
• the changeover catalyst might have a slightly higher REY content, i.e., about 5% ZSM-5 and about 10% REY.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Organic Chemistry (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Crystallography & Structural Chemistry (AREA)
• Materials Engineering (AREA)
• General Chemical & Material Sciences (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Catalysts (AREA)

Applications Claiming Priority (2)

Publications (2)

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Cited By (9)

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• 1985
  • 1985-06-18 AU AU43779/85A patent/AU581439B2/en not_active Ceased
  • 1985-06-19 EP EP85304366A patent/EP0167325A3/de not_active Withdrawn
  • 1985-07-04 MA MA20709A patent/MA20484A1/fr unknown
  • 1985-07-04 FI FI852655A patent/FI852655L/fi not_active Application Discontinuation
  • 1985-07-05 TR TR31374A patent/TR22689A/xx unknown
  • 1985-07-05 BR BR8503241A patent/BR8503241A/pt unknown

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